1. Field of the Invention
The present invention relates to magnetic heads, in particular, to a system for adjustably mounting a magnetic head in a recording or playback device.
2. Description of Related Art
Magnetic recording has gained widespread acceptance as a valuable method of data and information storage. To a large extent, this is because magnetic recording offers a method of storing vast amounts of information in a very compact form that can be readily and accurately retrieved. The popularity of magnetic recording is further enhanced because the storage media is relatively durable.
In typical magnetic recording systems the stored information is represented by magnetic fields of varying polarity and magnitude arranged in tracks along a magnetic medium such as a tape or disc. The tracks are formed by moving a magnetic medium with respect to a magnetic head. The magnetic head is provided with a coil which, when supplied with an electric current representative of the information to be stored, generates magnetic flux representative of the information to be stored. A corresponding magnetic flux is replicated in the magnetic media. During playback a recorded track is moved with respect to a magnetic head. The flux in the magnetic media generates a corresponding flux in the head which produces a current in the coil representative of the stored information.
Optimum operation of a recording device depends upon the proper orientation and position of the magnetic head. Otherwise, the use of an improperly oriented and positioned record head may result in the information being recorded in a manner that cannot be accurately retrieved on playback. Similarly, an improperly oriented or positioned playback head may result in the inaccurate retrieval of information even if the information was properly recorded. In either case, the integrity of the information storage system may be compromised and information may be lost.
Proper orientation and position of the magnetic head have become even more important because of attempts to increase the storage capacity of a magnetic media by increasing the number of tracks, or track density, on the media. Typically track density is increased through the sue of narrower track widths, closer track spacing, or both. As a result, in modern magnetic recording systems there is very little tolerance for error in the orientation and position of the magnetic head within the recorder.
Further, one of the advantages afforded by magnetic recording is that the media is designed for use on different devices. However, without a uniform orientation and position or the head, it may not be possible to use the media interchangeably on different devices. For example, if information is recorded on a machine having a head with a high azimuth angle, it may not be possible to accurately retrieve the information by using a machine having a very small azimuth angle for playback. As a result, to obtain optimum performance from magnetic recording or playback devices, it is essential to provide a head mounting mechanism that properly orients and positions the magnetic heads within such devices.
In the orientation and position of a magnetic head there are four different components which are important. The first three components are the azimuth, yaw (sometimes referred to as wrap), and zenith angles, which are rotation about the X, Y and Z axes, respectively. The fourth component is penetration, which is translation along the X axis.
In some magnetic recorders the head mounting mechanisms include complex arrangements of worm gears to adjust both the azimuth and zenith angles. However, because of the complexity of these systems, they are failure prone and are relatively expensive to manufacture and difficult to assemble and install. Further, such systems are unduly bulky and cannot be adapted for use on many compact magnetic recording devices.
In other head mounting systems, such as that described in U.S. Pat. No. 4,485,420, the head is fixed to a base plate which extends generally along the Z axis of the head. The base plate is then mounted within the recorder by attaching each and to a peg fixed to the frame of the recorder. By adjusting the height of the pegs, the azimuth angle of the head can be adjusted. However, these head mounting systems generally do not provide a means of adjusting the yaw or zenith angles, or the penetration of the head.
Another head mounting mechanism, of the type described in U.S. Pat. No. 4,550,352, incorporates an elastic body plate having a generally "T" shape. The base of the "T" is bent over itself and the head is affixed to the body member just above the bend. The cross bar of the body member is mounted between two pegs fixed to the recording device. As described above, the azimuth angle can be adjusted by varying the height of the pegs. One of the pegs is a spring loaded screw in order to facilitate this adjustment. Further, the body member is provided with another screw which adjusts the angle of the bend in the base of the "T," thereby adjusting the zenith angle of the head. However, this system typically does not allow adjustment of the yaw angle or head penetration. Further, because of the spring loaded screw, assembly and implementation of the system can be complex and expensive.